This invention relates to a transporter system for handling materials and, more particularly, to such a system which quickly and accurately transports material-laden pallets between multiple work stations on a production line.
Various types of vehicular systems have been utilized for transporting materials between work stations in assembly or production line operations. A typical application for such systems is in a manufacturing operation where components must be sequenced from a staging area through several machining centers, often then to powered conveyors for manual assembly operations. One such prior system employs an automatic guided vehicle (AGV) which runs on rubber tires and is controlled by a wire line. Auxiliary positioning devices are required at each work station as the AGV cannot itself be controlled with sufficient accuracy.
Another prior art system involves the use of a towveyor, typically with a coupling that may be selectively engaged with a tow line received in a channel in the floor of the production area. The towveyor, as well as the AGV, moves in only one direction and thus requires a continuous loop path in order to service all of the work stations. Accurate positioning at each work station is also a problem. Therefore, in both prior art systems a relatively large amount of floor space is required since movement is unidirectional, and the requirement of auxiliary positioning devices further increases the cost of the system.
In response thereto, we have invented a high-speed, bidirectional transporter for a multiple station production line which provides for the programmable pickup, transport and delivery of materials at non-sequential work stations along the production line. Our system generally comprises a self-propelled transporter which, by a rack and pinion drive, moves along a track that defines a course through the multiple work stations. Movement of the transporter to a work station is controlled by on-board, pre-programmed microcomputers. A turntable on the transporter has been particularly designed for pickup, transport and delivery of material-laden pallets associated with each work station. The turntable includes an extensible and retractable arm which is releasably coupled to a pallet so that the extensible and retractable motion of the arm is transferred to the coupled pallet. Upon movement of the transporter with pallet thereon to a work station, the turntable is rotated into alignment with a pickup and deposit stand at the station. Upon extension of the arm towards the stand, the coupled pallet slides along a guide assembly on the turntable and onto a similar guide assembly on the work station stand. Controlled rotation of the turntable disengages the coupling between the arm and the pallet so that the pallet remains on the stand as the arm is retracted. The transporter is then directed to another work station for pickup of a pallet on the associated stand.
Upon arrival at the next selected work station, the arm is extended and maneuvered into a position so as to couple the arm with the pallet. Once coupled, retraction of the arm moves the pallet along the guide assembly on the work station stand and onto the aligned guide assembly of the turntable of the transporter. The transporter is then propelled along the track for deposit of the coupled pallet at the next work station stand as above-described.
In addition to effecting the coupling and uncoupling of the arm with the pallet, the turntable imparts to the transporter the ability to transfer pallets off of both sides, the turntable being capable of 180.degree. of rotation. Accordingly, work stations may be located on both sides of the track in order to realize a substantial saving in floor space. At the command of the computer, the transporter moves to any station along the line in any order, and addresses either side of the track as required for pickup or delivery of the pallets.
It is, therefore, a general object of this invention to provide a transporter which quickly and accurately picks up, transports and delivers a material-laden pallet between work stations on a production line.
Another general object of this invention is to provide such a transporter which is bidirectional and capable of effecting transfer of pallets from both sides of its path of travel, thereby minimizing floor space and maximizing its speed and flexibility.
As a corollary to the foregoing object, it is an important aim of the invention to provide dual side capability through the use of a rotatable turntable which is controlled so as to address work stations on either side of the path of the transporter.
Furthermore, it is an important object of this invention to provide a transporter, as aforesaid, which has an extensible/retractable arm designed for novel pickup and deposit of a pallet from and at work stations of a production line.
Another object of this invention is to provide an arm, as aforesaid, which has a retracted transport position and an extended pickup or deposit position as controlled by drive assemblies on said transporter.
Still another object of this invention is to provide a coupling member on said arm which engages a coupling member on a pallet so as to provide for movement of said pallet concurrent with said arm.
A still further object of this invention is to provide an arm, as aforesaid, mounted on a transporter turntable which aligns the arm with each work station for pickup and deposit of a pallet thereon.
Another particular object of this invention is to provide a turntable, as aforesaid, which maneuvers said arm into or away from a releasably coupled position with a pallet at each work station.
A still further object of this invention is to provide a pallet stand at each work station which enhances pallet pickup and deposit by said transporter.
Another object of this invention is to provide pallet guide assemblies on said turntable and said stand which facilitate movement of a coupled pallet therebetween with a minimum of mechanical complexity.
Other objects and advantages of this invention will become apparent from the following description taken in connection with the accompanying drawings, wherein is set forth by way of illustration and example, an embodiment of this invention.